<!DOCTYPE html>
<html>
  <link rel='stylesheet' type='text/css' href='style.css'>
  <style>
    body > progress:nth-child(1)::-moz-progress-bar { width: 20px; }
    body > progress:nth-child(2)::-moz-progress-bar { width: 0px; }
    body > progress:nth-child(3)::-moz-progress-bar { width: 50%; }
    body > progress:nth-child(4)::-moz-progress-bar { width: 1em; }
    /* last one is for the default value: width=100%. */
  </style>
  <body>
    <!-- Those will be used to change padding/margin on ::-moz-progress-bar -->
    <progress></progress>
    <progress></progress>
    <progress></progress>
    <progress></progress>
    <progress></progress>
  </body>
</html>
